Sharks: Man-Eaters and Others

With suggestions that Americans turn to economic account some of the smaller species of the Atlantic Coast

The cow shark (Hexanchus griseus) is a primitive type of shark, peculiar in possessing six gill slits; most modern sharks have but five. Its single dorsal fin is also a distinguishing feature. It attains a length of twenty-six but is rare on United States coasts. (Courtesy United States Bureau of Fisheries)

The smallest shark known (Squaliolus laticaudus), adult female about four and one-half inches long. It is a deep-sea form represented at present by a single pair taken in Philippine waters, at a depth of one hundred and seventy fathoms. The deep-sea sharks are mostly small and dark colored but in structure do not differ markedly from other species. (Courtesy United States National Museum)

NOTES (except as otherwise noted, all date from 1916) 1. In this connection it is interesting to quote the opinion of Mr. J. T. Nichols of the American Museum and Mr. Robert C. Murphy of the Brooklyn Museum, who consider the circumstantial evidence sufficient to convict the white shark in spite of lack of definite proof against it:

“White sharks are so scarce that their habits are little known, but they are said to feed to some extent on big sea turtles, biting off their legs and even cutting through their shells. Of this species it may he said that judging from its physical make-up it would not hesitate to attack a man in the water. . . . Even a relatively small white shark, weighing two or three hundred pounds, might readily snap the largest human bones by a jerk of its body after it laid bitten through the flesh. The occurrence of the white shark near New York being almost as unprecedented as the attacks on bathers which happened simultaneously, the capture of a specimen by Mr. Schliesser confirms our belief that the white shark was responsible for the casualties.”

These views of Messrs. Nichols and Murphy are stated in full in the Magazine Section of the New York Times for August 6, 1916. —THE EDITOR.

2. The length attributed to the shark from which were obtained the famous “Port Fairy jaws” (from South Australia) is now known to be in error; I and several other experts have independently measured this jaw and we all agree it came from a shark between 16 and 17 feet in length; thus, it seems likely that the actual length of 16.5 feet was accidentally converted to 36.5 feet on the museum tag. In short: it is a transcriptional error. —R. Aidan Martin, 2006

3. This section refers to the so-called “megatooth shark” or megalodon, famous for its six- to seven-inch fossilized teeth. There is much controversy among paleoichthyologists (fossil fish experts) about the correct genus to use for this animal, which depends upon how one believes it related to the modern white shark, Carcharodon carcharias. Most paleontologists prefer the scientific name Carcharocles megalodon, although a few American experts continue to use the genus Carcharodon. Whichever genus they use, most paleoichthyologists agree that the megatooth shark was not a direct ancestor of the modern white shark, but more like a great uncle. Megalodon is now believed to have been considerably smaller than the classic AMNH reconstruction. Based on modern reconstructions of the jaws from complete (associated) fossil tooth sets, the megatooth shark is now believed to have reached lengths of about 50 feet. —R. Aidan Martin, 2006

4. Another form ranging from New York to the West Indies, was described in 1869 by Captain Atwood as Carcharias tigris but has not been recognized by later writers; it appears to be a distinct species and may be called Isurus tigris. It attains a length of ten feet or more. [The species Smith refers to is known as the shortfin mako and is now classified as Isurus oxyrinchus. It is one of four species of mackerel sharks (family Lamnidae) found off the Atlantic Coast of America. The others are the longfin mako (Isurus paucus), the white shark, and the porbeagle. The blue shark Smith refers to is not considered a different species from the porbeagle. —R. Aidan Martin, 2006]

5. Our commoner species are the sharp-nosed shark, Rhizoprionodon terraenovae, ranging from Massachusetts southward, numerous on the South Atlantic coast, and reaching a length of seven feet; Carcharhinus isodon, originally described from New York and now known from North Carolina and various other places on the shores of the western Atlantic; Negaprion brevirostris, reported by Radcliffe as fairly common on the North Carolina coast, the largest individual taken being over eight feet long; Carcharhinus leucas, a common form in the Gulf of Mexico and throughout the West Indies, attaining a length of ten to twelve feet; the black-finned shark, C. limbatus, of almost cosmopolitan distribution in tropical waters, known from our coast since 1875 when specimens were taken at Woods Hole, where also a five-foot individual was observed by the writer in July, 1916; the cub shark, C. lamia [now considered the same species as C. leucas —R. Aidan Martin, 2006], a common form on our southeast coast, represented in the American Museum of Natural History by a model of a specimen taken at Key West, an individual taken with rod and line in North Carolina in 1902 having been over nine feet long and live feet in girth; the dusky shark, C. obscurus, a very numerous species in southern Massachusetts in summer, common along the middle Atlantic coast, frequently taken with lines and nets, attaining a length of fourteen feet; the brown shark, C. plumbeus, often confused with several other species, not rare on the Atlantic coast from Cape Cod southward; and C. acronotus, a Cuban form of which a number of specimens were recently taken in North Carolina.